Syntheses Of Novel Quinolyl-triazene Reagents And Their Applications

Postgraduate: Zhou Neng Tutor: Prof. Zhao Shulin Cobalt and Nickel are essential trace elements for human body, the balance of their absorption and need do much to human's health ,whereas cadmium is important heavy metal pollutants .Therefore ,studies on novel reagents and color reactions as well as thereby establishing new methods for the determination of these metal ions are very important in the fields of life science and eviromental monitor .Triazene reagents have been widely employed in spectrohotometric determination of some metals, such as Cadmiun,Mercury,Nichel and Silver. In order to further probe their spectroscopic qualities and find more sensitive and selective reaction systems, three novel quinolyl- triazene reagents were designed and synthesized in this paper, i.e., 1-(6-nitro-2-benzothiazolyl)-3-(5- bromo-8- -quinolyl)-triazene (NBTBQT) ,1-(6-bromo-2-benzothiazolyl)-3-(5-bromo-8- -quinolyl)-triazene (BBTBQT),1-(6-nitro-2-benzothiazolyl)-3-(5-iodo-8- qui- -nolyl)-triazene (NBTIQT). In order to compare the functions of these reagents , 1-p-chlorobenzene-3-azobenzene- triazene (P-CBABT) was synthesized in the mean time。These new reagents were mainly prepared from 8-aminoquinoline,4-aminoazobenzene and 2-aminobenzothiazole through bromination and nitra -tion at first and then through diazotizations and couple reactions under lower temperature.And they were all recrystallized from etnanol ,DMF and distilled water or their mixing solutions, some of them were purified by column chroma -tography . The compositions and structures were characterized by element analysis, IR .while the hydrolysis constant of hydrogen of -N=N-NH- were tested as : p-CBABT, pKa=12.32; NBTBQT, pKa=8.80; BBTBQT, pKa=9.38.In this paper, these new reagents' color reactions with Cd(Ⅱ),Ni(Ⅱ),Co(Ⅱ) and Ag(Ⅰ) have been studied in detail. The experimental results follow below : (1) in the presence of CTMAB, NBTBQT reacts with Ni(Ⅱ) and Co(Ⅱ) to form a blue complex with a molar ratio of 2:1 in a borax buffer solution .The molar absorptivity of Ni-R and Co-R is 2.16×105L.mol-1.cm-1 at 633nm and 1.94×105 L.mol-1.cm-1 at 655nm, respectively. Beer's law are obeyed in the range of 0~6μg/25mL for them.(2) in a borax buffer solution BBTBQT reacts with Ni(Ⅱ) and Co(Ⅱ) to form a blue complex in the presence of CTMAB and CPB , with a molar ratio of 2:1.The molar absorptivity of Ni-R and Co-R is 1.84×105 -L.mol-1.cm-1 at 618nm and 1.55×105L.mol-1.cm-1 at 640nm, respectively. Beer'slaw is obeyed in the range of 0~6μg/25mL and 0~7μg/25mL, respectively. (3) In the presence of CTMAB, NBTIQT reacts with Ni(Ⅱ) and Co(Ⅱ) to form a blue complex with a molar ratio of 2:1 in a borax buffer solution .The molar absor -ptivity of Ni-R and Co-R is 1.50×105L.mol-1.cm-1 at 624nm and 1.59×105 -L.mol-1.cm-1 at 657nm, respectively. Beer's law are obeyed in the range of 0~6μg/25mL and 0~6μg/25mL ,respectively。(4) (1) in the presence of Triton-X-100 p-CBABT reacts with Cd(Ⅱ),Ni(Ⅱ) and Ag(Ⅰ) to form a orange-red complex with a molar ratio of 2:1 , 3:1 and 1:1 in a borax buffer solution .The molar absorptivity of Cd-R and Ni-R is 1.21×105L.mol-1.cm-1 at 493nm ,1.25×105 -L.mol-1.cm-1 at 504nm and 6.20×104L.mol-1.cm-1 at 504nm respectively. Beer's law is obeyed in the range of 0~25μg/25mL , 0~7μg/25mL and 0~10μg/25mL ,respectively.In this paper ,based on the color reactions of these new reagents ,seven methods for the determinations of Cd(Ⅱ),Ni(Ⅱ),Co(Ⅱ) and Ag(Ⅰ) have been established ,and these methods have been applied to determine trace nickel in aluminum alloy ,trace cobalt in injection solution of vitamin B12 and in drainage sediment ,trace cadmiun in waste water from industry and silver in button-cell with satisfactory results.A conclusion can be got from these data that these novel reagents exhibit highly sensitive color reactions with these metals listed with better selectivity. Among them NBTBQT and BBTBQT are one of the most sensitive reagents for the determina...